# Audit Types

Arlo software supports a number of RLA types to provide a statistically sound method for any paper ballot jurisdiction. VotingWorks' RLA team can help you choose which RLA type is best for your jurisdiction.

### **Ballot Polling**

Consists of the retrieval of randomly selected ballots to confirm the outcome of the election. Only requires secure storage of paper ballots. The selected voted ballots are hand tallied, and the resulting manual vote counts are checked against the total vote counts.  

### **Batch Comparison**

Consists of the retrieval of randomly selected batches of ballots. A batch may consist of all the ballots cast in a precinct, on a specific ballot scanner, or smaller tabulated batches. Those batches are hand tallied and counts are compared to the reported results, batch by batch, to confirm the outcome of the election.  Requires vote counts by batch. 

### **Ballot Comparison**

Consists of very precise retrieval of randomly selected ballots.  Each ballot is compared to the voting system’s cast vote record (CVR) to confirm the outcome of the election. Requires CVRs from the voting system and each ballot to be stored in the exact order it was scanned. The imprinting of a unique identifier (in no way connected to the voter) is recommended.

### **Hybrid**

Combination of ballot polling & ballot comparison types. If some of a state’s jurisdictions have the technology to conduct ballot comparison audits and others do not, the hybrid model allows for an audit that utilizes both types.

### **Full Manual Tally**

In some cases, an RLA may result in a full manual tally of all ballots.  This may occur when the margin of the contest being audited is so close that the number of ballots to be audited is high and a full manual tally would be more efficient or when the results of multiple rounds detect anomalies in the results and require a full manual tally to confirm the outcome. 

|                                                                                                         | **Ballot Polling**                                                                     | **Batch Comparison**                                                                                                | **Ballot Comparison**                                                                                                                                             | **Hybrid**                                                                                                                 |
| ------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| **Requirements**                                                                                        | <p>\*Paper ballots</p><p>\*Recording of number of ballots stored in each container</p> | <p>\*Paper ballots</p><p>\*Recording of number of ballots in each stored container</p><p>\*Vote counts by batch</p> | <p>\*Paper ballots</p><p>\*Recording of number of ballots stored in each container</p><p>\*Cast Vote Records (CVRs)</p><p>\*Imprinting of ballots recommended</p> | Combination of ballot polling & ballot comparison requirements.                                                            |
| <p><strong>Ballots to be audited</strong> - for an election with a 4% margin & 5% risk limit</p><p></p> | **3,769**                                                                              | Depends on the number of ballots and batches.  For 1 million ballots, **77 batches** (\~25,600 ballots)             | **170**                                                                                                                                                           | <p><strong>170-3,769</strong></p><p></p><p>The more ballots subject to ballot comparison, the smaller the sample size.</p> |


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